Often mistaken for tree sap, honeydew is a sugar-rich sticky liquid, secreted by aphids (greenflies) and some scale insects as they feed on plant sap. When their mouthpart penetrates the phloem, the sugary, high-pressure liquid is forced out of the gut’s terminal opening. Honeydew can often be found on leaves and plants especially in the summer months & literally falls from canopies and will bond to any surface beneath. Commonly, honeydew hardens after being deposited on a surface which in turn makes it harder to remove over time.